How do you place a custom marker in the virtual world using the Measurement Toolkit?

Placing a custom marker in the virtual world using the Measurement Toolkit involves a straightforward interaction with the interface. By clicking the Add button followed by selecting the desired location for the marker, the user can precisely position it where needed within the virtual environment. This method allows for direct visual feedback as the user can see the effect of their action immediately, ensuring that the placement is exactly where intended.

Other options may suggest actions that either don't specifically relate to adding a marker or involve more complex methods of positioning that might not offer the same level of immediacy or accuracy. The simplicity and directness of the click action after selecting the Add button make it the most effective choice for this task.